172 research outputs found
Relativistic Hartree-Bogoliubov Calculation of Specific Heat of the Inner Crust of Neutron Stars
We calculate the specific heat of the inner crust of neutron stars within a
local-density approximation to an improved relativistic Hartree-Bogoliubov
theory. Non-uniformness of the system enhances the specific heat in particular
at low temperatures. The degree of enhancement is similar to that in the
spherical phase of Elgar{\o}y et al. We examine a schematic interpolation
between the results of Broglia et al. adopting the Gogny force and ours based
on the Lagrangian of the relativistic mean field model.Comment: 5 pages, Talk presented at the 3rd JAERI Symposium on Science of
Hadrons under Extreme Conditions, January 200
Vector DC magnetic-field sensing with reference microwave field using perfectly aligned nitrogen-vacancy centers in diamond
The measurement of vector magnetic fields with high sensitivity and spatial
resolution is important for both fundamental science and engineering
applications. In particular, magnetic-field sensing with nitrogen-vacancy (NV)
centers in diamond is a promising approach that can outperform existing
methods. Recent studies have demonstrated vector DC magnetic-field sensing with
perfectly aligned NV centers, which showed a higher readout contrast than NV
centers having four equally distributed orientations. However, to estimate the
azimuthal angle of the target magnetic field with respect to the NV axis in
these previous approaches, it is necessary to apply a strong reference DC
magnetic field, which can perturb the system to be measured. This is a crucial
problem, especially when attempting to measure vector magnetic fields from
materials that are sensitive to applied DC magnetic fields. Here, we propose a
method to measure vector DC magnetic fields using perfectly aligned NV centers
without reference DC magnetic fields. More specifically, we used the direction
of linearly polarized microwave fields to induce Rabi oscillation as a
reference and estimated the azimuthal angle of the target fields from the Rabi
frequency. We further demonstrate the potential of our method to improve
sensitivity by using entangled states to overcome the standard quantum limit.
Our method of using a reference microwave field is a novel technique for
sensitive vector DC magnetic-field sensing.Comment: 10 pages, 8 figure
Quantum metrology based on symmetry-protected adiabatic transformation: Imperfection, finite time duration, and dephasing
The aim of quantum metrology is to estimate target parameters as precisely as
possible. In this paper, we consider quantum metrology based on
symmetry-protected adiabatic transformation. We introduce a ferromagnetic Ising
model with a transverse field as a probe and consider the estimation of a
longitudinal field. Without the transverse field, the ground state of the probe
is given by the Greenberger-Horne-Zeilinger state, and thus the Heisenberg
limit estimation of the longitudinal field can be achieved through parity
measurement. In our scheme, full information of the longitudinal field encoded
on parity is exactly mapped to global magnetization by symmetry-protected
adiabatic transformation, and thus the parity measurement can be replaced with
global magnetization measurement. Moreover, this scheme requires neither
accurate control of individual qubits nor that of interaction strength. We
discuss the effects of the finite transverse field and nonadiabatic transitions
as imperfection of adiabatic transformation. By taking into account finite time
duration for state preparation, sensing, and readout, we also compare
performance of the present scheme with a classical scheme in the absence and
presence of dephasing.Comment: Presentation (title, structure, etc.) is improved. New results and
new references are adde
Photoelectron detection from transient species in organic semiconducting thin films by dual laser pulse irradiation
An Nd3+:YAG pulsed laser was employed as a light source for two-photon photoemission from organic semiconducting thin films in low vacuum and air. Photoionization by the two-photon process was confirmed in both the environments by measuring photoemission current. By constructing a pumpāprobe system, photoemissions from transient species formed by the pump light irradiation were detected by probe light irradiation as a result of a linear increase in the photocurrent with the pump power via a one-photon process. Thus, we propose a novel method called two-photon photoelectron yield spectroscopy to determine the excited-state energy levels in ambient environments
Evaluating contributions of natural language parsers to proteināprotein interaction extraction
Motivation: While text mining technologies for biomedical research have gained popularity as a way to take advantage of the explosive growth of information in text form in biomedical papers, selecting appropriate natural language processing (NLP) tools is still difficult for researchers who are not familiar with recent advances in NLP. This article provides a comparative evaluation of several state-of-the-art natural language parsers, focusing on the task of extracting proteināprotein interaction (PPI) from biomedical papers. We measure how each parser, and its output representation, contributes to accuracy improvement when the parser is used as a component in a PPI system
Alloy design concept for bcc-T2 silicide-B2 aluminide multicomponent alloys
For the development of refractory metal-based high temperature bcc alloys, the phase equilibrium between bcc (Nb-Mo) and T2 (Nb, Mo)5(Si,B)3 has been investigated. Bcc matrix phase is for toughening at ambient temperatures, and T2 phase is for strengthening and also for oxidation resistance. However, the oxidation resistance of T2 phase is still under investigation. B2-NiAl phase has been utilized as coating materials for Ni-based superalloys for many years. However, addition of Al and transition metal element such as Ni and Fe results in the formation of brittle Laves phases in refractory metal-based bcc alloys.
In the present study it is found that additive element selection in terms of atomic size control is effective to avoid the formation of Laves phase. From this phase stability viewpoint, a three-phase alloy composed of Nb, Mo, Si, B, Ni and Al is proposed as a first step for designing three-phase alloys.
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Parametrizations of triaxial deformation and E2 transitions of the wobbling band
By the very definition the triaxial deformation parameter is related
to the expectation values of the K=0 and K=2 components of the intrinsic
quadrupole tensor operator. On the other hand, using the same symbol
"", various different parametrizations of triaxial deformation have
been employed, which are suitable for various types of the mean-field
potentials. It is pointed out that the values of various "" are quite
different for the same actual triaxial deformation, especially for the large
deformation; for example, the difference can be almost a factor two for the
case of the triaxial superdeformed bands recently observed in the Hf and Lu
nuclei. In our previous work, we have studied the wobbling band in Lu nuclei by
using the microscopic framework of the cranked Nilsson mean-field and the
random phase approximation, where the most serious problem is that the
calculated B(E2) value is about factor two smaller. It is shown that the origin
of this underestimation can be mainly attributed to the small triaxial
deformation; if is used the same triaxial deformation as in the analysis of the
particle-rotor model, the calculated B(E2) increases and gives correct
magnitude compared with the experimental data.Comment: 10 pages, 9 figure
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